Breast cancer is a highly significant cause of morbidity and mortality worldwide. There are over 1.3 million cases of breast cancer diagnosed globally each year with more than 450,000 deaths related to the disease (Jemal A, Bray F, Center M, et al. Global cancer statistics. CA Cancer J Clin, 2011; 61(2):69-90).
The HER2 (ErbB2) receptor tyrosine kinase is a member of the epidermal growth factor receptor (EGFR) family of transmembrane receptors. Overexpression of HER2 is observed in approximately 20% of human breast cancers and is implicated in the aggressive growth and poor clinical outcomes associated with these tumors (Slamon et al (1987) Science 235:177-182). HER2 protein overexpression can be determined using an immunohistochemistry based assessment of fixed tumor blocks (Press M F, et al (1993) Cancer Res 53:4960-70).
Trastuzumab (CAS 180288-69-1, HERCEPTIN®, huMAb4D5-8, rhuMAb HER2, Genentech) is a recombinant DNA-derived, IgG1 kappa, monoclonal antibody that is a humanized version of a murine anti-HER2 antibody (4D5) that selectively binds with high affinity in a cell-based assay (Kd=5 nM) to the extracellular domain of HER2 (U.S. Pat. Nos. 5,677,171; 5,821,337; 6,054,297; 6,165,464; 6,339,142; 6,407,213; 6,639,055; 6,719,971; 6,800,738; 7,074,404; Coussens et al (1985) Science 230:1132-9; Slamon et al (1989) Science 244:707-12; Slamon et al (2001) New Engl. J. Med. 344:783-792). Trastuzumab has been shown, in both in vitro assays and in animals, to inhibit the proliferation of human tumor cells that overexpress HER2 (Hudziak et al (1989) Mol Cell Biol 9:1165-72; Lewis et al (1993) Cancer Immunol Immunother; 37:255-63; Baselga et al (1998) Cancer Res. 58:2825-2831). Trastuzumab is a mediator of antibody-dependent cellular cytotoxicity, ADCC (Lewis et al (1993) Cancer Immunol Immunother 37(4):255-263; Hotaling et al (1996) [abstract]. Proc. Annual Meeting Am Assoc Cancer Res; 37:471; Pegram M D, et al (1997) [abstract]. Proc Am Assoc Cancer Res; 38:602; Sliwkowski et al (1999) Seminars in Oncology 26(4), Suppl 12:60-70; Yarden Y. and Sliwkowski, M. (2001) Nature Reviews: Molecular Cell Biology, Macmillan Magazines, Ltd., Vol. 2:127-137).
HERCEPTIN® was approved in 1998 for the treatment of patients with HER2-overexpressing metastatic breast cancers (Baselga et al, (1996) J. Clin. Oncol. 14:737-744) that have received extensive prior anti-cancer therapy, and has since been used in over 300,000 patients (Slamon D J, et al. N Engl J Med 2001; 344:783-92; Vogel C L, et al. J Clin Oncol 2002; 20:719-26; Marty M, et al. J Clin Oncol 2005; 23:4265-74; Romond E H, et al. T N Engl J Med 2005; 353:1673-84; Piccart-Gebhart M J, et al. N Engl J Med 2005; 353:1659-72; Slamon D, et al. [abstract]. Breast Cancer Res Treat 2006, 100 (Suppl 1): 52). In 2006, the FDA approved HERCEPTIN® (trastuzumab, Genentech Inc.) as part of a treatment regimen containing doxorubicin, cyclophosphamide and paclitaxel for the adjuvant treatment of patients with HER2-positive, node-positive breast cancer.
Trastuzumab-MCC-DM1 (T-DM1, trastuzumab emtansine, ado-trastuzumab emtansine, KADCYLA®), a novel antibody-drug conjugate (ADC) for the treatment of HER2-positive breast cancer, is composed of the cytotoxic agent DM1 (a thiol-containing maytansinoid anti-microtubule agent) conjugated to trastuzumab at lysine side chains via an MCC linker, with an average drug load (drug to antibody ratio) of about 3.5. After binding to HER2 expressed on tumor cells, T-DM1 undergoes receptor-mediated internalization, resulting in intracellular release of cytotoxic catabolites containing DM1 and subsequent cell death.
The U.S. Food and Drug Administration approved ado-trastuzumab emtansine, marketed under the tradename KADCYLA®, on Feb. 22, 2013 for the treatment of patients with HER2-positive, metastatic breast cancer who previously received treatment with trastuzumab and a taxane.
Pertuzumab (also known as recombinant humanized monoclonal antibody 2C4, rhuMAb 2C4, PERJETA®, Genentech, Inc, South San Francisco) represents the first in a new class of agents known as HER dimerization inhibitors (HDI) and functions to inhibit the ability of HER2 to form active heterodimers or homodimers with other HER receptors (such as EGFR/HER1, HER2, HER3 and HER4). See, for example, Harari and Yarden Oncogene 19:6102-14 (2000); Yarden and Sliwkowski. Nat Rev Mol Cell Biol 2:127-37 (2001); Sliwkowski Nat Struct Biol 10:158-9 (2003); Cho et al. Nature 421:756-60 (2003); and Malik et al. Pro Am Soc Cancer Res 44:176-7 (2003)
Pertuzumab blockade of the formation of HER2-HER 3 heterodimers in tumor cells has been demonstrated to inhibit critical cell signaling, which results in reduced tumor proliferation and survival (Agus et al. Cancer Cell 2:127-37 (2002)).
Pertuzumab has been evaluated in Phase II studies in combination with trastuzumab in patients with HER2-positive metastatic breast cancer who have previously received trastuzumab for metastatic disease. One study, conducted by the National cancer Institute (NCI), enrolled 11 patients with previously treated HER2-positive metastatic breast cancer. Two out of the 11 patients exhibited a partial response (PR) (Baselga et al., J Clin Oncol 2007 ASCO Annual Meeting Proceedings; 25:18 S (June 20 Supplement): 1004. The results of a Phase II neoadjuvant study evaluating the effect of a novel combination regimen of pertuzumab and trastuzumab plus chemotherapy (Docetaxel) in women with early-stage HER2-positive breast cancer, presented at the CTRC-AACR San Antonio Breast Cancer Symposium (SABCS), Dec. 8-12, 2010, showed that the two HER2 antibodies plus Docetaxel given in the neoadjuvant setting prior to surgery significantly improved the rate of complete tumor disappearance (pathological complete response rate, pCR, of 45.8 percent) in the breast by more than half compared to trastuzumab plus Docetaxel (pCR of 29.0 percent), p=0.014.
Pertuzumab, marketed under the tradename PERJETA®, was approved in 2012 for the treatment of patients with advanced or late-stage (metastatic) HER2-positive breast cancer. HER2-positive breast cancers have increased amounts of the HER2 protein that contributes to cancer cell growth and survival.
On Sep. 30, 2013, the U.S. Food and Drug Administration granted accelerated approval to PERJETA® (pertuzumab) as part of a complete treatment regimen for patients with early stage breast cancer (EBC) before surgery (neoadjuvant setting). PERJETA® is the first FDA-approved drug for the neoadjuvant treatment of breast cancer.
There is a need in the art for additional safe and effective agents that target HER2 for treatment of HER2-associated conditions, such as breast cancer, for use in monotherapy and combination therapy. The invention fulfills that need and provides other benefits.